Bacterial Blight

Based on what we can see in the picture, your lilic may also have a bacterial or fungal infection, not uncommon. It’s hard to be certain without seeing the entire plant to see how many leaves are affected and where the damage is most prevalent. If you can send us a photo of the entire plant that would be helpful. In the meantime, don’t overhead water, which can spread infection. Of course, it’s impossible to avoid overhead watering with the rain you’re experiencin. Also, remove all leaf debris that may have fallen off and discard it in the garbage, not the compost pile. If you want to remove the most infected leaves now, make sure to wipe your garden sheers off with alcohol wipes between cuts as precaution. When plants are stressed, it’s best not to fertilize them, which can stress them further. Send us another photo of the entire plant and we’ll try to narrow down the possibilities. You can send multiple images. Kudos to you for paying close attention to your plants!